Chalkboards and whiteboards with erasable markers for interactive discussions have widespread use in business and educational settings. Various electronic whiteboards provide for electronic recordation of markings such as figures, words and characters handwritten by a user onto the whiteboard for later printout, review, and/or transmission. Typical electronic whiteboards include a resistive membrane stretched over a rigid substrate, an electronics module for determining the position of an instrument such as a pen or stylus used to write on the whiteboard, and a computer for processing and storing the coordinates of the pen as it moves over the whiteboard.
Disadvantages with current whiteboards include the inability for participants dispersed throughout a room to provide handwritten input to a drawing being discussed and developed on a whiteboard. Therefore, participants who want to contribute to a drawing being developed on the whiteboard must crowd around the whiteboard in order to gain access and provide handwritten input. The problem of accessing the whiteboard is magnified as the setting gets larger, such as in a large conference room or lecture hall where a greater number of people want to share and collaborate on ideas. In addition, most whiteboards are simply not visible to people seated in the back rows of a large conference room or lecture hall. Another disadvantage with current whiteboards that are able to record handwritten input (e.g., electronic whiteboards) is that they are often bulky and difficult to transport due to the resistive membrane and rigid substrate typically used to sense handwritten input. This can create problems for a lecturer who travels to numerous locations to give interactive presentations. Yet another significant disadvantage with current whiteboards is that they do not provide the ability to mark up pre-existing drawings or images. Rather, the drawings on the whiteboard are developed from scratch.
Projection systems are also commonly used in business and educational settings for interactive discussions. Unlike electronic whiteboards, projection systems provide pre-existing images for interactive discussions. For example, data projectors are devices that accept image data from a computer and project images onto a screen or white wall. An advantage of data projectors is the ease with which hardcopies of a presentation can be printed and made available to participants. Another advantage with projectors in general is their ability to make projected images large enough to be visible to people seated in back rows of a large conference room or lecture hall.
Data projectors initially used only cathode ray tubes (CRT) to create an image which was magnified and projected. However, CRT data projectors are quite large and difficult to transport. Therefore, LCD (liquid crystal display) data projectors are now more commonly used. LCD projectors form an image on an LCD panel which is backlit by a very bright halogen lamp to illuminate the panel and project the image through a lens onto a screen or white wall. A significant advantage of an LCD data projector is that it can be very small and easy to transport.
A disadvantage of data projectors (e.g., an LCD projector) for collaborative purposes, is that they do not provide the ability for discussion participants to provide handwritten input to projected images. Therefore, interaction between a speaker and an audience is limited to verbal interaction. More recently, data projectors have been developed that include electronic white boards. Although projecting images onto a whiteboard permits handwritten input, the problem of having participants crowd around the whiteboard in order to provide handwritten input to an image remains. In addition, use of a whiteboard with a projector reduces the projected image size to the size of the whiteboard, and thus reduces visibility for people seated in the back rows of a large conference room or lecture hall. Furthermore, the illumination of an image onto a whiteboard often visually overpowers underlying markings made to a whiteboard. Thus, it is often difficult to see the handwritten input. In addition, although an electronic whiteboard permits the recordation of handwritten markings for later printout, review, and/or transmission, such markings are of little use if not combined with the originally projected image being marked up.
Accordingly, the need exists for an interactive projection system that permits numerous participants dispersed throughout a room, including a large conference room or lecture hall, to collaboratively generate and discuss drawings that can easily be recorded for printout, review, and/or transmission. The need also exists for such a system to provide pre-existing images that can be collaboratively marked up and recorded for printout, review, and/or transmission.